DSP demo with pluto

dsp_pluto.jl

### A Pluto.jl notebook ###
# v0.12.3

using Markdown
using InteractiveUtils

# This Pluto notebook uses @bind for interactivity. When running this notebook outside of Pluto, the following 'mock version' of @bind gives bound variables a default value (instead of an error).
macro bind(def, element)
    quote
        local el = $(esc(element))
        global $(esc(def)) = Core.applicable(Base.get, el) ? Base.get(el) : missing
        el
    end
end

# ╔═╡ d7641af0-e514-11ea-159d-4b0ea0294203
using Plots, SampledSignals, DSP, PlutoUI

# ╔═╡ 57b70420-e514-11ea-1a37-11efa5f2726c
@bind audio HTML("""
<audio id="player"></audio>
<button class="button" id="stopButton">Stop</button>
<script>
  const player = document.getElementById('player');
  const stop = document.getElementById('stopButton');

  const handleSuccess = function(stream) {
    const context = new AudioContext({ sampleRate: 44100 });
    const analyser = context.createAnalyser();
    const source = context.createMediaStreamSource(stream);

    source.connect(analyser);

    const bufferLength = analyser.frequencyBinCount;

    let dataArray = new Float32Array(bufferLength);
    let animFrame;

    const streamAudio = () => {
      animFrame = requestAnimationFrame(streamAudio);
      analyser.getFloatTimeDomainData(dataArray);
      player.value = dataArray;
      player.dispatchEvent(new CustomEvent("input"));
    }

    streamAudio();

    stop.onclick = e => {
      source.disconnect(analyser);
      cancelAnimationFrame(animFrame);
    }
  }

  navigator.mediaDevices.getUserMedia({ audio: true, video: true })
    .then(handleSuccess)
</script>
<style>
.button {
  background-color: darkred;
  border: none;
  border-radius: 12px;
  color: white;
  padding: 15px 32px;
  text-align: center;
  text-decoration: none;
  display: inline-block;
  font-size: 16px;
  font-family: "Alegreya Sans", sans-serif;
  margin: 4px 2px;
  cursor: pointer;
}
</style>
""")

# ╔═╡ dca970a2-e514-11ea-2975-0be3321223c8
begin
        aud = Array(audio)
        plot(domain(SampleBuf(aud, 44100)), SampleBuf(aud, 44100), legend=false, ylims=(-1,1))
end

# ╔═╡ e8a895c6-0a98-11eb-018e-0f7b893f0350
@bind cutoff Slider(50:20_000)

# ╔═╡ 9e5881e2-0a94-11eb-1415-edbd569e1287
begin
        hp_resp = Highpass(cutoff; fs=44_100)
        hp_desg = Butterworth(4)
        lp_resp = Lowpass(cutoff; fs=44_100)
        lp_desg = Butterworth(4)
        hp = filt(digitalfilter(hp_resp, hp_desg), aud)
        lp = filt(digitalfilter(lp_resp, lp_desg), aud)
end

# ╔═╡ edcb4148-0a93-11eb-13d2-4bb829db282b
begin
        plot(hp, label="high frequencies")
        plot!(lp, label="looo") # xlim=(0,20_000))
end

# ╔═╡ 2fd6d3d4-0a96-11eb-39e2-8f1d0f8eacdc
full_fft, hpfft, lpfft = periodogram.([aud, hp, lp])

# ╔═╡ f5dd1f78-0a93-11eb-3a53-51019f79be01
begin
        plot(hpfft.freq, pow2db.(hpfft.power), label="hp")
        plot!(lpfft.freq, pow2db.(lpfft.power), label="lp")
        plot!(full_fft.freq, pow2db.(full_fft.power), label="ap")
end

# ╔═╡ Cell order:
# ╠═57b70420-e514-11ea-1a37-11efa5f2726c
# ╠═d7641af0-e514-11ea-159d-4b0ea0294203
# ╠═dca970a2-e514-11ea-2975-0be3321223c8
# ╠═e8a895c6-0a98-11eb-018e-0f7b893f0350
# ╠═9e5881e2-0a94-11eb-1415-edbd569e1287
# ╠═edcb4148-0a93-11eb-13d2-4bb829db282b
# ╠═2fd6d3d4-0a96-11eb-39e2-8f1d0f8eacdc
# ╠═f5dd1f78-0a93-11eb-3a53-51019f79be01